摘要：
The structural mechanism existing in the V-shape pier-girder joint in long-span V-shape rigid frame composite arch bridge is complicated, especially for the case in the Xiaolan Channel long-span major bridge project, which requires comprehensive research on the local stress and nonlinear behavior after cracking through model test. Using nonlinear space finite element model, the local stress and post cracking nonlinear mechanical behaviors at the V-shape pier-girder joint are studied. In this paper, the design principles, loading modes, procedures and arrangement of gauging points applied in the model are introduced at first. Comparing the experimental results with the theoretical values, the local stress distributions of the V-shape pier-girder joint under different loading conditions are obtained. Furthermore, the nonlinear behavior of the V-shape pier-girder joint is investigated by analyzing the relationships between loads and reinforcement strains in negative moment area and the relationships between loads and deflections. The study shows that the load transfer in V-shape pier girder joint is reasonable. The joint has good ductibility, post-deformation and residual carrying capacity. The design of the V-shape rigid frame composite arch bridge meets the criteria. It is also expected that the results presented in this paper would be useful as references for future research and design of V-shape rigid frame composite arch bridges and joints.

摘要：
In order to investigate mechanic behaviors of the orthotropic deck welding conformation details of highway steel bridge, take Zhongdu Yangtze River Bridge located in Jiangjin of Chongqing district as an engineering background, the 3-dimension spatial section model of steel box girder was firstly established based on the numerical finite element method, and then the stress level of welding conformation including the top plate of orthotropic deck, stiffening rib and transverse diaphragm was studied. The numerical analyzed results show that the stress level of welding conformation is mainly influenced by the second system and the third system. The mechanical performance of box girder is specifically represented as global bending action, global shearing action and local supporting action, which reflects significant local stress state. Also, the degree of the above mentioned actions for different conformation details is different.

摘要：
To study the mechanical performance and stability of tied-arch bridge under structural defects and damages, limited element modal of Panzhihua Luoguo Jinshajiang Bridge was established and analyzed. Firstly, some typical damage models and their influence factors were presented. Then, based on the model established, change of suspender force caused by arch rib lineation defect, hanger lineation defect and boom failure was calculated respectively. The stability safety factor under the load group composed of dead load, live load and wind was calculated as well as the second-class nonlinear stability safety factor under structural initial defect. Calculation results shows that, suspender forces were more sensitive to arch's vertical defect than to transverse defect. While, short hangers were more sensitive to lineation defect than long ones, and secondary inner force in short booms were bigger than in long ones. The result also tells that lateral wind is bad to lateral stability. Lift wind, somehow, makes positive contribution to structure's in-plane stability. Structural initial defect can draw down the second-class stability safety factor under geometric nonlinear condition.

摘要：
Basket handle arch bridge with reinforced concrete shortens the distance between the arch rib compared with parallel arch rib bridge, improves the lateral stability, predecessors have done a lot of research on basket handle narrow arch bridge, but the study of wide span arch bridge is insufficient, conduct load test on a wide basket handle arch bridge which 33m wide and mainspan is 90m, the test results show that the large width-span ratio arch bridge has higher bearing capacity, but vertical bearing capacity is not improved, the dynamic coefficient increases when the speed is higher than 30km/h, the measured dynamic coefficient at jumpy driving is relatively large, the dynamic coefficient is significant when jumpy driving speed is 10-15km/h.

摘要：
Based on the study on existing experimental research on steel-concrete composite connection, the experiment set up of the steel-concrete composite connection with cells of the Yongjiang River Bridge, is presented. The design theory of model test, comparison of model test program, design of steel and concrete, design of shear connectors and the deviation of model test are discussed. Especially for the design issues of shear connectors in a scale model, the finite element model of the small size of the shear connectors release test was established to calculate carrying capacity and shear stiffness. The constitutive relationship and failure criteria are discussed. The designing method of shear connectors in scale model test was proposed.

摘要：
In this study, a dynamic response analysis procedure is proposed and applied to investigate the dynamic responses of a straddle-type concrete-filled steel tube tied arch bridge under train and truck loadings. A numerical model of the coupled monorail train-bridge system is established to investigate the dynamic behaviors of the bridge under moving trains. A refined three-dimensional finite element model is built for the bridge and a 15 degrees-of-freedom vehicle model is presented for the train. The numerical model is validated using in-situ test results and then used to analyze the dynamic displacement and acceleration of the bridge and the trains on the bridge. Based on the simulation results, the impact factor of the bridge is investigated and the riding comfort of the trains is evaluated. The investigation results show that the impact factor of vehicle loads reaches the maximum value when the resonance of the bridge is induced by the moving vehicles. The effect of train braking predominates the longitudinal vibration of the bridge but is negligible in the transverse and vertical directions. The vehicle speed is the dominating factor for the riding comfort of the train.